383 research outputs found
Reproductive Health of Bass in the Potomac, USA, Drainage: Part 1. Exploring the Effects of Proximity to Wastewater Treatment Plant Discharge
Intersex (specifically, testicular oocytes) has been observed in male smallmouth bass (SMB; Micropterus dolomieu) and other centrarchids in the South Branch of the Potomac River, USA, and forks of the Shenandoah River, USA, during the past five years. This condition often is associated with exposure to estrogenic endocrine-disrupting chemicals in some fish species, but such chemicals and their sources have yet to be identified in the Potomac. In an attempt to better understand the plausible causes of this condition, we investigated the reproductive health of bass sampled up- and downstream of wastewater treatment plant (WWTP) effluent point sources on the Potomac River in Maryland, USA. Smallmouth bass were sampled from the Conococheague Creek and the Monocacy River, and largemouth bass (LMB; Micropterus salmoides) were collected near the Blue Plains WWTP on the mainstem of the Potomac River. Chemical analyses of compounds captured in passive samplers at these locations also were conducted. A high prevalence of intersex (82â100%) was identified in male SMB at all sites regardless of collection area. A lower prevalence of intersex (23%) was identified in male LMB collected at the Blue Plains site. When up- and downstream fish were compared, significant differences were noted only in fish from the Conococheague. Differences included condition factor, gonadosomatic index, plasma vitellogenin concentration, and estrogen to testosterone ratio. In general, chemicals associated with wastewater effluent, storm-water runoff, and agriculture were more prevalent at the downstream sampling sites. An exception was atrazine and its associated metabolites, which were present in greater concentrations at the upstream sites. It appears that proximity to effluent from WWTPs may influence the reproductive health of bass in the Potomac watershed, but inputs from other sources likely contribute to the widespread, high incidence of testicular oocytes
The risk of colectomy and colorectal cancer after appendectomy in patients with ulcerative colitis:a systematic review and meta-analysis
Background: Appendectomy decreases the risk of developing ulcerative colitis [UC], and is suggested to have a beneficial effect on the clinical course of established UC. However, recent studies showed no significantly decreased colectomy rate, and moreover an apparently increased risk of colorectal cancer [CRC]. We aimed to investigate the suggested correlation in a meta-analysis and to analyse possible confounding factors. Methods: A systematic review and meta-analysis were performed using MEDLINE, EMBASE, and the Cochrane Library. Data from studies describing the influence of appendectomy on colectomy and CRC were extracted from published reports. Exclusion criteria were patients aged <18 years, non-UC, and animal studies. Results: From 891 studies, 13 studies evaluating 73 323 UC patients [appendectomy n = 2859] were included. All studies, except one, were rated as poor quality. Overall, colectomy rate in appendectomised and non-appendectomised patients was not significantly different (odds ratio [OR] 1.25, 95% confidence interval [CI] 0.88-1.77, I2 = 53%). The proportion of colectomies undertaken for CRC or high-grade dysplasia [HGD] was significantly higher after appendectomy [OR 2.85, 95% CI 1.40-5.78, I2 = 32%], with 50% of the colectomies indicated for CRC/HGD compared with 9.4% in non-appendectomised patients. Possible additional confounding factors were a longer UC disease duration, less medication use, and a higher prevalence of primary sclerosing cholangitis [PSC] in appendectomised patients. Conclusions: Appendectomy in established UC is associated with apparently higher rates of subsequent CRC/HGD, but this appears to be due to inequalities in at-risk exposure between groups, presumably secondary to positive clinical effects of appendectomy on disease symptoms. This finding emphasises the importance of regular endoscopic surveillance in this patient group
The relationship of urinary albumin excretion rate to ambulatory blood pressure and erythrocyte sodium-lithium countertransport in NIDDM
The counterrotating core and the black hole mass of IC1459
The E3 giant elliptical galaxy IC1459 is the prototypical galaxy with a fast
counterrotating stellar core. We obtained one HST/STIS long-slit spectrum along
the major axis of this galaxy and CTIO spectra along five position angles. We
present self-consistent three-integral axisymmetric models of the stellar
kinematics, obtained with Schwarzschild's numerical orbit superposition method.
We study the dynamics of the kinematically decoupled core (KDC) in IC1459 and
we find it consists of stars that are well-separated from the rest of the
galaxy in phase space. The stars in the KDC counterrotate in a disk on orbits
that are close to circular. We estimate that the KDC mass is ~0.5% of the total
galaxy mass or ~3*10^9 Msun. We estimate the central black hole mass M_BH of
IC1459 independently from both its stellar and its gaseous kinematics. Some
complications probably explain why we find rather discrepant BH masses with the
different methods. The stellar kinematics suggest that M_BH = (2.6 +/-
1.1)*10^9 Msun (3 sigma error). The gas kinematics suggests that M_BH ~
3.5*10^8 Msun if the gas is assumed to rotate at the circular velocity in a
thin disk. If the observed velocity dispersion of the gas is assumed to be
gravitational, then M_BH could be as high as ~1.0*10^9 Msun. These different
estimates bracket the value M_BH = (1.1 +/- 0.3)*10^9 Msun predicted by the
M_BH-sigma relation. It will be an important goal for future studies to assess
the reliability of black hole mass determinations with either technique. This
is essential if one wants to interpret the correlation between the BH mass and
other global galaxy parameters (e.g. velocity dispersion) and in particular the
scatter in these correlations (believed to be only ~0.3 dex). [Abridged]Comment: 51 pages, LaTeX with 19 PostScript figures. Revised version, with
three new figures and data tables. To appear in The Astrophysical Journal,
578, 2002 October 2
Restorative surgery after colectomy for ulcerative colitis in England and Sweden:observations from a comparison of nationwide cohorts
Ultraviolet Imaging Observations of the cD Galaxy in Abell 1795: Further Evidence for Massive Star Formation in a Cooling Flow
We present images from the Ultraviolet Imaging Telescope of the Abell 1795
cluster of galaxies. We compare the cD galaxy morphology and photometry of
these data with those from existing archival and published data. The addition
of a far--UV color helps us to construct and test star formation model
scenarios for the sources of UV emission. Models of star formation with rates
in the range \sim5-20M_{\sun}yr indicate that the best fitting models
are those with continuous star formation or a recent ( Myr old) burst
superimposed on an old population. The presence of dust in the galaxy,
dramatically revealed by HST images complicates the interpretation of UV data.
However, we find that the broad--band UV/optical colors of this cD galaxy can
be reasonably matched by models using a Galactic form for the extinction law
with . We also briefly discuss other objects in the large UIT
field of view.Comment: To appear in the Astrophysical Journal. 14 AAS preprint style pages
plus 7 figure
Chronic fatigue syndrome
Objective. To acknowledge the dinical syndrome chronic fatigue syndrome (CFS) and outline the diagnostic criteria and reasonable management.Outcomes. Attempt at containment of treatment cost and improvement of the quality of care of patients with CFS.Evidence. Delphi-type commentary from 20 expert clinicians and appropriate organisations. Limited literature survey.Values. To clarify the reasonable management of CFS amid conflicting clinical opinion on a condition qf concern to patients, funders and doctors, An adaptation:of an existing guideline was sent to organisations and individuals for comment. Comments received were included in this guideline where possible.Benefits, harms and costs. To acknowledge a clinical syndrome with a reasonable approach to management considering the cost implications. No cost analysis was done.Recommendations. To recommend the following: (I) diagnostic criteria for CFS; (il) potential differential diagnoses and possible investigations; and (iil) management protocol.Validation. The draft guidelines were subjected to external review by individual doctors who are acknowledged CFS treaters, doctor groups and the patient support group. There were major disputes about the content, with the responses falling into two groups: thosewho do not believe CFS is a distinguishable illness, and those who do.Developer and funding. The Committee for Science and Education, Medical Association of South Africa, Endorsements. Medical Association of South Africa and national health care organisations (see list at the end of the document)
WFPC2 Observations of the Cooling Flow Elliptical in Abell 1795
We present WFPC2 images of the core of the cooling flow cD galaxy in Abell
1795. An irregular, asymmetric dust lane extends 7 \h75 kpc in projection to
the north-northwest. The dust shares the morphology observed in the H
and excess UV emission. We see both diffuse and knotty blue emission around the
dust lane, especially at the ends. The dust and emission features lie on the
edge of the radio lobes, suggesting star formation induced by the radio source
or the deflection of the radio jets off of pre-existing dust and gas. We
measure an apparent R significantly less than 3.1, implying that the
extinction law is not Galactic in the dust lane, or the presence of line
emission which is proportional to the extinction. The dust mass is at least
2 M\solar\ and is more likely to be 6.5 M\solar.Comment: 14 pages, LaTeX, Figure 4 included, Postscript Figs. 1-3 available at
ftp://astro.nmsu.edu/pub/JASON/A1795/, accepted for publication in ApJ
Letter
STEllar Content and Kinematics from high resolution galactic spectra via Maximum A Posteriori
We introduce STECKMAP (STEllar Content and Kinematics via Maximum A
Posteriori), a method to recover the kinematical properties of a galaxy
simultaneously with its stellar content from integrated light spectra. It is an
extension of STECMAP (astro-ph/0505209) to the general case where the velocity
distribution of the underlying stars is also unknown.
%and can be used as is for the analysis of large sets of data. The
reconstructions of the stellar age distribution, the age-metallicity relation,
and the Line-Of-Sight Velocity Distribution (LOSVD) are all non-parametric,
i.e. no specific shape is assumed. The only a propri we use are positivity and
the requirement that the solution is smooth enough. The smoothness parameter
can be set by GCV according to the level of noise in the data in order to avoid
overinterpretation. We use single stellar populations (SSP) from PEGASE-HR
(R=10000, lambda lambda = 4000-6800 Angstrom, Le Borgne et al. 2004) to test
the method through realistic simulations. Non-Gaussianities in LOSVDs are
reliably recovered with SNR as low as 20 per 0.2 Angstrom pixel. It turns out
that the recovery of the stellar content is not degraded by the simultaneous
recovery of the kinematic distribution, so that the resolution in age and error
estimates given in Ocvirk et al. 2005 remain appropriate when used with
STECKMAP. We also explore the case of age-dependent kinematics (i.e. when each
stellar component has its own LOSVD). We separate the bulge and disk components
of an idealized simplified spiral galaxy in integrated light from high quality
pseudo data (SNR=100 per pixel, R=10000), and constrain the kinematics (mean
projected velocity, projected velocity dispersion) and age of both components.Comment: 12 pages, 6 figures, accepted for publication in MNRA
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